Administration of angiotensin-converting enzyme (ACE) inhibitors is common medical practice for the treatment of a variety of disease conditions, including: cardiac and renal diseases, diabetes, and hypertension (high blood pressure). Several combined ACE and neutral endopeptidase (NEP) inhibitors are presently under investigation or are awaiting regulatory approval for the treatment of the aforementioned disease conditions. However, the administration of an ACE and/or a vasopeptidase inhibitor (referred to herein as an ACE/vasopeptidase inhibitor) is contraindicated for subjects with a history of angioedema due to the potential severity of this side effect, which can be so severe as to result in death. Approximately 0.1% to 1.0% of the population receiving an ACE inhibitor is predicted to be susceptible to developing at least one episode of angioedema during treatment. This percentage might be even higher, especially for subjects taking a vasopeptidase inhibitor. Also, these inhibitors are often administered over long periods of time because the illnesses that they treat are often chronic conditions. This could increase the chances of a subject developing angioedema over a course of treatment.
Angioedema is an uncommon, but serious, side effect of ACE and vasopeptidase inhibitors. Currently, it is not possible to accurately predict which subjects are at risk to develop angioedema when taking an ACE or vasopeptidase inhibitor; however it is known that approximately 0.1% to 1.0% or more of the subjects receiving an ACE or vasopeptidase inhibitor will develop angioedema as a side effect. The variation in susceptibility to vasopeptidase-associated angioedema depends, in part, on the subgroup of the population that is analyzed. For example, African Americans are particularly susceptible to ACE inhibitor associated angioedema.
In patients who develop angioedema while taking one of these medications, it is difficult to determine if the angioedemic condition arose in response to the medication or due to some other occurrence. For example, certain allergic reactions can result in angioedema. The current standard in practice is to employ a treatment other than an ACE/vasopeptidase inhibitor, if a patient has a known history of angioedema, or to halt treatment with ACE/vasopeptidase inhibitors if a patient presents with symptoms of angioedema or it is learned after-the-fact that the patient has a history of angioedema. Most practitioners, however, consider these alternative therapies to be less effective in treating the original condition than ACE/vasopeptidase inhibitor therapy.
What is needed, therefore, are tests, assays, and biological markers for identifying patients that are at increased risk for developing angioedema related to treatment with ACE/vasopeptidase inhibitors, as compared to the general population or a matched population. Such assays would allow the continued use of ACE/vasopeptidase inhibitors in subjects that have a reduced susceptibility to angioedema and the rational regulation of their use in susceptible subjects. The present invention solves these and other problems, in part by providing biological markers and diagnostic tests and kits that are preferably employed early on in treatment, thereby averting complications.